He was a member of the Fosters, who were in charge of security and helped take care of the grove. Neman valued money above anything else and could be bought off by anyone. He helped Kassia capture the Fourth Doctor, Adric and Tremas, although they were released with Nyssa's help.
After Melkur took over the Source and became the new Keeper, Neman was loyal to the Master in his position of Keeper of Traken in the guise of the Melkur. The Master ordered Neman to arrest the Doctor, which Neman failed to do. When Melkur had the Doctor and Tremas temporarily under his control, Melkur forced Tremas to execute Neman because he had failed to capture the Doctor and Tremas. (TV: The Keeper of Traken)